lecture05

lecture05 - 20.106J Systems Microbiology Lecture 5 Prof....

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20.106J – Systems Microbiology Lecture 5 Prof. DeLong ¾ Reading: p533-555, Bioenergetics and Metabolic Diversity ¾ Today: o Basic modes of energy generation o Thermodynamics of growth (continued) o Applications of microbial chemolithotrophy and anaerobic respiration ± Review: Most of the energy in the atmosphere today comes from photons from the sun – it’s like a big solar cell o Cyclic photophosphorylation – extracting energy via excited electrons and the electron transport chain ± The fundamentals of how you get to ATP is the same for phototrophs and autotrophs ± There is a lot of diversity in anoxygenic phototrophs o Using photon energy to strip electrons off of water ± You’re not going to use up your source of energy ± Waste product is oxygen – allows other, heterotrophic life o Rhodopsins – Haloarchaea – live in hypersaline habitats ± They can live in salt crystals if there’s water available ± They get energy from light via a simple protein – rhodopsin Organic molecule absorbs a photon, changes shape, and then the whole protein changes, allowing the cell to transport an electron from inside the cell to outside Æ concentration gradient There are two types of microbial rhodopsins: light-driven ion pumps and sensory rhodopsins We have sensory rhodopsins in our eyes There are different sorts of rhodopsins that exist in bacteria
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lecture05 - 20.106J Systems Microbiology Lecture 5 Prof....

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